• Korean Journal of Microbiology
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• v.54 no.4
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• pp.379-383
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• 2018

Beer is the most popular alcoholic fermentation product, but its high purine content has been known to be associated with hyperuricemia and gout. In this study, we examined whether the purine content of beer could be lowered by changing the fermentation temperature during beer-brewing. We brewed beers at different temperatures, $10^{\circ}C$ and $20^{\circ}C$, that are two typical beer-brewing conditions for bottom- and top-fermentation, respectively, and the contents of the representative purines, adenine, guanine, and xanthine in each beer were measured by high performance liquid chromatography. As a result, the total purine content of the beer fermented at $10^{\circ}C$ was lower than that of fermented beer at $20^{\circ}C$. Especially, the content of adenine was lowered significantly.

• Journal of Dairy Science and Biotechnology
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• v.37 no.2
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• pp.83-93
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• 2019

Food spoilage by fungi is responsible for considerable food waste and economical losses. Among the food products, fermented dairy products are susceptible to deterioration due to the growth of fungi, which are resistant to low pH and can proliferate at low storage temperatures. For controlling fungal growth in dairy products, potassium sorbate and natamycin are the main preservatives used, and natamycin is approved by most countries for use in cheese surface treatment. However, a strong societal demand for less processed and preservative-free food has emerged. In the dairy products, lactic acid bacteria (LAB) are naturally present or used as cultures and play a key role in the fermentation process. Fermentation is a natural preservation technique that improves food safety, nutritional value, and specific organoleptic features. Production of organic acids is one of the main features of the LAB used for outcompeting organisms that cause spoilage, although other mechanisms such as antifungal peptides obtained from the cleavage of food proteins and competition for nutrients also play a role. More studies for better understanding these mechanisms are required to increase antifungal LAB available in the market.

• Culinary science and hospitality research
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• v.2
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• pp.183-207
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• 1996

This study is to investigate the effect on the quality and properties of bread affected by licorice extract addition. The measurements of the farinograph, extensograph and amylograph on dough are carried out. And the evaluations of volumetric changes during fermentation, shape of bread crumb, sensory test, firmness are obtained. The obtained results are as follows. 1. Proximate compositions of licorice extract are as follows: moisture 73.7%, crude protein 4.1%, crude lipid 2.8%, crude ash 1.4%. 2. Water absoorption, arrival time dough development time mechanical tolerence index and valorimeter value are increased but stability is decreased with the addition of licorice extract. 3. The resistance to extension is increased but extensibility is decreased with the addition of licorice extract. 4. The initial pasting and highest viscosity temperatures are not affected but the highest viscosity is steepy decreased over 1.0% addition of licorice extract. 5. The volume of dough during fermentation and specific volume of bread is decreased with the addition of licorice extract. 6. The grain of bread is to be rough and irregular and the firmness is increased with the addition of licorice extract. 7. The records of sensory test are decreased with the addition of licorice extract.

• Journal of Microbiology and Biotechnology
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• v.9 no.1
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• pp.22-31
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• 1999

Saccharomyces fermentati and Leuconostoc mesenteroides were isolated from a traditional kimchi, and then the Leu. mesenteroides was mutated to the acid-tolerant mutant Leu. mesenteroides M-l00. In the result of growth properties in MRS broth with various pHs adjusted with HCl and acid solution (latic acid:acetic acid=1:2), an acid-tolerant mutant Leu. mesenteroides M-100 showed more increased ability for growth than its wild strain at various temperatures. The strains were used as starters for the fermentation of kimchi. The experiments were performed with classified experimental groups (Group I, control kimchi; Group II, addition of YK-19 only; Group III, addition of M-100 only; Group IV, addition of mixture of M-100 and YK-19), and their pH, total acidity, reducing sugars content, organic acid productivity, organoleptic tests, and microfloral changes were compared. As a result, in pH and acidity, the optimal ripening period of Group IV was about 13.5 days (i.e. from the 8.5 to 22 days of fermentation). This result indicates that the optimal ripening period of Group IV was about 1.5 times longer than that of Group I. Furthermore, Group IV was edible to 28 days of fermentation. In addition, high contents of succinc acid was observed in Group IV. Group IV was also highly ranked on the organoleptic test. During the fermentation of kimchi, the number of Leuconostoc sp. in group I reduced after 7 days; however, the number of Leuconostoc sp. in Group II, III, and IV decresed after 14 days of fermentation. An especially high number of Leu. sp. was observed in Group IV, and this gave better flavor of kimchi than any other during the whole fermentation period. Citric acid, tartaric acid, succinic acid, fumaric acid, and lactic acid were detected in the kimchi, and a significant increase in the concentration of lactic acid during fermentation was observed in the all experimental groups.

• Journal of the Korea Organic Resources Recycling Association
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• v.8 no.1
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• pp.97-102
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• 2000

This study was carried out to investigate the effects of operating temperatures on decomposition and physicho-chemical properties of household food wastes in a fermentation dryer, which was manufactured by Samwoo Co. Ltd. The household food wastes of 100 kg can be put and dried in this dryer at once. The experiments were performed at each temperature of $35^{\circ}C$, $45^{\circ}C$, $55^{\circ}C$ and $70^{\circ}C$ for two days respectively. The samples taken at the fixed time were dried at $105^{\circ}C$ and analyzed to find the decomposition rate and the concentration of each substance. The results obtained were as follows: The decomposition rate at 35 and $70^{\circ}C$ was the highest and showed the similar tendency during the experimental period. The higher the operating temperature was, the faster the water content of the composting material reduced. pH value increased at the operating temperature of 55 and $70^{\circ}C$ and was higher than at the other operating temperatures. Nitrogen content did not show any tendency during the experimental period. $P_2O_5$ and CaO content increased during the experimental period but MgO, $K_2O$ and NaCl were not accumulated. Cu content based on dry matter was in the range of ND~100.4 mg/kg and Cd, Pb and Cr were not detected.

• Journal of the Korean Society of Food Science and Nutrition
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• v.38 no.6
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• pp.742-749
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• 2009

In order to establish the basic scientific data on the fermentation characteristics of chonggak kimchi (CGK), we studied with CGKs prepared at different seasons and stored at various temperatures ($5{\sim}23^{\circ}C$). Changes in pH and acidity of CGK fermented at different temperatures were typical. However, acidity of summer CGK stored under $15^{\circ}C$ did not reach 1.0% since the amount of reducing sugar in the summer radish was lower by over 1% than the ones from the other seasons. Growths for Leuconostoc and Lactobacillus spp. over 8.0 logCFU/mL were observed in CGKs fermented above $10^{\circ}C$. Changes in Max G, cutting force, of CGK from different seasons were apparent. Max Gs for spring and summer CGK were decreased immediately right after storage while Max Gs for winter CGKs were increased slowly during storage. According to the results of sensory evaluation, CGKs revealed the highest overall acceptability when acidity of kimchi reached $0.7{\pm}0.1%$ under the given fermentation condition. However, CGK prepared with radish from winter or summer season tasted better than the one made in the spring. But the edible periods for winter CGKs were longer, compared with summer CGKs fermented at the same temperature. In conclusion, CGK fermented at $10^{\circ}C$ in the winter season gives a better taste with longer edible duration than the other CGKs.

• Korean journal of food and cookery science
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• v.24 no.5
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• pp.617-625
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• 2008

In this study, we evaluated changes in the quality characteristics of Godulbaegi kimchi during storage at $20^{\circ}C$ and $5^{\circ}C$. The pH and reducing sugar of Godulbaegi kimchi decreased, and the total acidity and color differences increased with increasing storage time at both temperatures. The vitamin C contents of the Godulbaegi kimchi decreased during the first 15 days of storage at $20^{\circ}C$, then increased for 18 days. The total dietary fiber contents were significantly higher in the fresh Godulbaegi kimchi than in the fermented Godulbaegi kimchi samples. Antioxidative activity was significantly higher in the fresh Godulbaegi kimchi than in the fermented kimchi.

• Journal of Environmental Science International
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• v.22 no.6
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• pp.723-732
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• 2013

This study was carried out to investigate changes of protease and amylase activities and nitrogen content in Chungkookjang prepared by Bacillus subtilis S8 and different soybean. Amino-type nitrogen and ammonia-type nitrogen contents increased with an increase in fermentation time and was the highest in black soybean Chungkookjang. The number of viable cells increased up to 24 h of fermentation at all temperatures tested; especially, their levels were the highest at $40^{\circ}C$. Protease activity was the highest in black soybean Chungkookjang. ${\alpha}$-amylase activity increased significantly up to 6 h of fermentation at $30^{\circ}C$ and $40^{\circ}C$ and then maintained constantly. It also increased up to 30-36 h of fermentation at $45^{\circ}C$ and then decreased. ${\beta}$-amylase activity was the highest in black soybean Chungkookjang at $35^{\circ}C$ and $40^{\circ}C$ and in yellow soybean Chungkookjang at $45^{\circ}C$. Production pattern of reducing sugar was similar to that of ${\beta}$-amylase. Amino-type nitrogen, viable cell number and reducing sugar content and ${\beta}$-amylase activity was the highest in Chungkookjang fermented at $40^{\circ}C$. Considering amino-type and ammonia-type nitrogen contents, Chungkookjang fermentation using yellow soybean was favorable. However, the fermentation using black soybean was favorable, considering protease and amylase activities and reducing sugar content.

• Journal of the Korean Society of Food Science and Nutrition
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• v.45 no.1
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• pp.155-159
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• 2016

The objective of this study was to investigate the effect of fermentation temperature on quality characteristics of apple wine. Apple wine mashes were fermented in 15, 20, and $25^{\circ}C$ water bathes for 9 days. The pH levels of all samples were below 4 from 24 h of fermentation until the end. Total acidities of 0.05% acetic acid solution were 7.8, 7.4, and 7.0% in the 15, 20, and $25^{\circ}C$ fermented samples, respectively. The evaporation of esters generated by combining alcohol and organic acids might be the reason for lower total acidity for high temperature fermentation. Alcohol contents of the 20 and $25^{\circ}C$ fermented samples were 6.5 and 6.6% (v/v), respectively, whereas that of the $15^{\circ}C$ fermented sample was 5.6% (v/v) and significantly lower than the others (P<0.05). Methanol contents were 0.68, 0.82, and 1.69 mg/L in the 15, 20, and $25^{\circ}C$ fermented samples, respectively. Fermentation at higher temperatures generated higher methanol content in apple wine. On the other hand, acetaldehyde contents were 3.43, 2.39, and 1.02 mg/L in the 15, 20, and $25^{\circ}C$ fermented samples, respectively, due to the lower boiling point of acetaldehyde ($20.2^{\circ}C$). Based on the results, a fermentation temperature of $20{\sim}25^{\circ}C$ is effective for apple wine fermentation.

• Food Science and Preservation
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• v.17 no.6
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• pp.826-834
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• 2010

We investigated the temperature changes during processing and quality characteristics of seven preparations of Byeok-hyang-ju described in ancient documents. During fermentation, treatments with intervals longer than 7 days to the second mashing kept temperatures below room temperature. The process with the shortest interval (2 days) between the second and third mashings maintained a preparation temperature above $28^{\circ}C$ for the longest period. As fermentation proceeded, the pH gradually decreased. Titratable acidities increased prior to the second mashing, and then decreased. Amino acid levels increased gradually during all fermentations except for that of method 5 (the lowest level of raw material addition). Ethanol content increased rapidly to the time of second mashing with all methods except method 2. This method featured a short interval between the first and second mashing. Upon sensory evaluation, the best overall acceptability was provided by method 3.